Conjugated polymers

ABSTRACT

The invention relates to novel polymers containing repeating units based on benzo[2,1,3]thiadiazole-5,6-dicarboxylic acid bis-ester, monomers and methods for their preparation, their use as semiconductors in organic electronic (OE) devices, especially in organic photovoltaic (OPV) devices, and to OE and OPV devices comprising these polymers.

FIELD OF THE INVENTION

The invention relates to novel polymers containing repeating units basedon benzo[2,1,3]thiadiazole-5,6-dicarboxylic acid bis-ester, monomers andmethods for their preparation, their use as semiconductors in organicelectronic (OE) devices, especially in organic photovoltaic (OPV)devices, and to OE and OPV devices comprising these polymers.

BACKGROUND OF THE INVENTION

In recent years there has been growing interest in the use ofconjugated, semiconducting polymers for electronic applications. Oneparticular area of importance is organic photovoltaics (OPV). Conjugatedpolymers have found use in OPVs as they allow devices to be manufacturedby solution-processing techniques such as spin casting, dip coating orink jet printing. Solution processing can be carried out cheaper and ona larger scale compared to the evaporative techniques used to makeinorganic thin film devices. Currently, polymer based photovoltaicdevices are achieving efficiencies up to 8%.

The conjugated polymer serves as the main absorber of the solar energy,therefore a low band gap is a basic requirement of the ideal polymerdesign to absorb the maximum of the solar spectrum.

A commonly used strategy to narrow the band gap of conjugated polymersis to utilize an alternating copolymer consisting of both electron richdonor units and electron deficient acceptor units within the polymerbackbone. An acceptor unit that is known in prior art and has shown goodphotovoltaic performances when used in copolymers is2,1,3-benzothiadiazole (BTZ) (see J. Chen, Y. Cao, Acc. Chem. Res.,2009, 42 (11), 1709):

However, these polymers can have limited solubility in commonly usedorganic solvents, which can inhibit their suitability for devicemanufacturing methods based on solution processing). Therefore, thepresence of additional solubilising functionality on the BTZ unit isdesirable to expand the range of suitable processing solvents and theirsolid loading within these solvents.

More recently polymers containing5,6-bis(octyloxy)-benzo[2,1,3]thiadiazole ((OR)₂BTZ) units have beenprepared, like for example copolymers with fluorene having the followingstructure:

These polymers show improved solubility due to the flexible alkoxy sidechains (see J. Bouffard, T. M. Swager, Macromolecules, 2008, 41(15),5559).

Additionally, where the (OR)₂BTZ unit is flanked by two thiophene units,like in the copolymers shown below, the polymer retains the planarconformation of the back bone which is required to achieve the narrowband gaps and good charge carrier mobility required for OPV applications(see R. Qin, W. Li, C. Li, C. Du, C. Veit, H.-F. Schleiermacher, M.Andersson, Z. Bo, Z. Liu, O. Inganas, U. Wuerfel, F. Zhang, J. Am. Chem.Soc., 2009, 131, 14612; M. Helgesen, S. A. Gevorgyan, F. C. Krebs, R. A.J. Janssen, Chem. Mater., 2009, 21(19), 4669; W. Li, R. Qin, Y. Zhou, M.Andersson, F. Li, C. Zhang, B. Li, Z. Liu, Z. Bo, F. Zhang, Polymer,2010, 51, 3031):

However, these polymers suffer from open circuit potentials (V_(oc)) inOPV bulk-heterojunction devices which are not attaining the theoreticalmaximum of ˜1.15 V in a polymer/PCBM device (see J. C. Bijleveld, R. A.M. Verstrijden, M. M. Wienk, R. A. J. Janssen, Applied Physics Letters,2010, 97, 073304).

Therefore, there is still a need for organic semiconducting (OSC)materials that are easy to synthesize, especially by methods suitablefor mass production, show good structural organization and film-formingproperties, exhibit good electronic properties, especially a high chargecarrier mobility, good processibility, especially a high solubility inorganic solvents, and high stability in air. Especially for use in OPVcells, there is a need for OSC materials having a low bandgap, whichenable improved light harvesting by the photoactive layer and can leadto higher cell efficiencies, and do not suffer from open circuitpotentials (V_(oc)) in OPV bulk-hetero-junction devices, or do so to alower extent than polymers from prior art.

It was an aim of the present invention to provide compounds for use asorganic semiconducting materials that do not have the drawbacks of priorart materials as described above, are easy to synthesize, especially bymethods suitable for mass production, and do especially show goodprocessibility, high stability, good solubility in organic solvents,high charge carrier mobility, and a low bandgap. Another aim of theinvention was to extend the pool of OSC materials available to theexpert. Other aims of the present invention are immediately evident tothe expert from the following detailed description.

The inventors of the present invention have found that these aims can beachieved by providing conjugated polymers containing BTZ units that aresubstituted in 5- and 6-position by ester groups to givebenzo[2,1,3]thiadiazole-5,6-dicarboxylic acid bis-ester:

wherein E is CO—O or O—CO and R¹ and R² are carbyl groups like forexample alkyl or aryl.

It was found that conjugated polymers based on this unit show goodprocessability and high solubility in organic solvents, and are thusespecially suitable for large scale production using solution processingmethods. At the same time, they show a low bandgap, high charge carriermobility and high oxidative stability and are promising materials fororganic electronic OE devices, especially for OPV devices. Also, theaddition of two electron withdrawing ester groups onto the BTZ acceptorunit deepens the HOMO level in order to achieve a higher open circuitpotential (V_(oc)) in an OPV bulk-heterojunction device versus a devicecontaining a polymer based upon BTZ or (OR)₂BTZ while maintaining thesame band-gap.

SUMMARY OF THE INVENTION

The invention relates to a conjugated polymer comprising one or moreidentical or different repeating units of formula I:

wherein an asterisk indicates a link to a neighboured group,

-   W is S, Se, O or NR^(x),-   E¹, E² are —O—C(O)— or —C(O)—O—,-   R^(x) is H or straight-chain, branched or cyclic alkyl with 1 to 30    C atoms, in which one or more non-adjacent C atoms are optionally    replaced by —O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—, O—C(O)—O—, —CH═CH—    or —C≡C— and in which one or more H atoms are optionally replaced by    F, Cl, Br, I or CN,-   R¹, R² are, each independently of one another, an optionally    substituted C₁₋₄₀ carbyl or hydrocarbyl group.

The invention further relates to a conjugated polymer comprising one ormore repeating units which contain a unit of formula I and/or containone or more units (hereinafter also referred to as Ar¹, Ar² and Ar³)selected from aryl and heteroaryl units that are optionally substituted,and wherein at least one of the repeating units in the polymer containsat least one unit of formula I.

Preferably, R¹ and R² in formula I are selected from straight-chain,branched or cyclic alkyl with 1 to 35 C atoms, in which one or morenon-adjacent C atoms are optionally replaced by —O—, —S—, —C(O)—,—C(O)—O—, —O—C(O)—, —O—C(O)—O—, —CR⁰═CR⁰⁰— or —C≡C— and in which one ormore H atoms are optionally replaced by F, Cl, Br, I or CN, or denotearyl, heteroaryl, aryloxy, heteroaryloxy, arylcarbonyl,heteroarylcarbonyl, arylcarbonyloxy, heteroarylcarbonyloxy,aryloxycarbonyl or heteroaryloxycarbonyl having 4 to 30 ring atoms thatis unsubstituted or substituted by one or more non-aromatic groups R³,wherein

-   R⁰ and R⁰⁰ are independently of each other H or optionally    substituted C₁₋₄₀ carbyl or hydrocarbyl,-   R³ is on each occurrence identically or differently F, Br, Cl, —CN,    —NC, —NCO, —NCS, —OCN, —SCN, —C(O)NR⁰R⁰⁰, —C(O)X⁰, —C(O)R⁰, —NH₂,    —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, optionally    substituted silyl, carbyl or hydrocarbyl with 1 to 40 C atoms that    is optionally substituted and optionally comprises one or more    hetero atoms, or P-Sp-,-   P is a polymerisable or crosslinkable group,-   Sp is a spacer group or a single bond, and-   X⁰ is halogen.

The conjugated polymers according to the present invention arepreferably selected of formula II:—[(Ar¹—U—Ar²)_(x)—(Ar³)_(y)]_(n)—  IIwherein

-   U is on each occurrence identically or differently a unit of formula    I as described above and below,-   Ar¹, Ar², Ar³ are, on each occurrence identically or differently,    and independently of each other, aryl or heteroaryl that is    optionally substituted, preferably by one or more groups R³ as    defined above, and one or both of Ar¹ and Ar² may also denote a    single bond,-   Y¹ and Y² are independently of each other H, F, Cl or CN,-   x is on each occurrence identically or differently 0, 1 or 2,    wherein in at least one repeating unit, i.e. in at least one unit    —[(Ar¹—U—Ar²)_(x)—(Ar³)_(y)]—, x is 1,-   y is on each occurrence identically or differently 0, 1 or 2,-   n is an integer >1.

The invention further relates to monomers containing a unit of formulaI, which are suitable for the preparation of conjugated polymers asdescribed above and below.

The invention further relates to a mixture or blend comprising one ormore polymers according to the present invention and one or moreadditional compounds or polymers which are preferably selected fromcompounds and polymers having one or more of semiconducting, chargetransport, hole or electron transport, hole or electron blocking,electrically conducting, photoconducting or light emitting properties.

The invention further relates to a formulation comprising one or morepolymers, mixtures or blends according to the present invention andoptionally one or more solvents, preferably selected from organicsolvents.

The invention further relates to the use of polymers, mixtures, blendsand formulations according to the present invention as charge transport,semiconducting, electrically conducting, photoconducting or lightemitting material in optical, electrooptical, electronic,electroluminescent or photoluminescent components or devices.

The invention further relates to a charge transport, semiconducting,electrically conducting, photoconducting or light emitting material orcomponent comprising one or more polymers, polymer blends offormulations according to the present invention.

The invention further relates to an optical, electrooptical orelectronic component or device comprising one or more polymers, polymerblends, formulations, components or materials according to the presentinvention.

The optical, electrooptical, electronic electroluminescent andphotoluminescent components or devices include, without limitation,organic field effect transistors (OFET), thin film transistors (TFT),integrated circuits (IC), logic circuits, capacitors, radio frequencyidentification (RFID) tags, devices or components, organic lightemitting diodes (OLED), organic light emitting transistors (OLET), flatpanel displays, backlights of displays, organic photovoltaic devices(OPV), solar cells, laser diodes, photoconductors, photodetectors,electrophotographic devices, electrophotographic recording devices,organic memory devices, sensor devices, charge injection layers, chargetransport layers or interlayers in polymer light emitting diodes(PLEDs), organic plasmon-emitting diodes (OPEDs), Schottky diodes,planarising layers, antistatic films, polymer electrolyte membranes(PEM), conducting substrates, conducting patterns, electrode materialsin batteries, alignment layers, biosensors, biochips, security markings,security devices, and components or devices for detecting anddiscriminating DNA sequences.

DETAILED DESCRIPTION OF THE INVENTION

The monomers and polymers of the present invention are easy tosynthesize and exhibit several advantageous properties, like a lowbandgap, a high charge carrier mobility, a high solubility in organicsolvents, a good processability for the device manufacture process, ahigh oxidative stability and a long lifetime in electronic devices.

In addition, they show the following advantageous properties:

i) Additional solubility can be introduced into the polymer by inclusionof the two solubilising ester groups or co-monomers containing multiplesolubilising groups

ii) The addition of two electron withdrawing ester groups onto the BTZacceptor unit can modify the electronic energies (HOMO/LUMO levels) ofthe polymer, particularly a deepening of the HOMO level in order toachieve a higher open circuit potential (V_(oc)) in an OPVbulk-heterojunction device versus a device containing a polymer basedupon BTZ.iii) Additional fine-tuning of the electronic energies (HOMO/LUMOlevels) by either further modification of thebenzo[1,2-b;4,5-b′]dithiophene core or co-polymerisation withappropriate co-monomer(s) should afford candidate materials for organicphotovoltaic applications

Above and below, the term “polymer” generally means a molecule of highrelative molecular mass, the structure of which essentially comprisesthe multiple repetition of units derived, actually or conceptually, frommolecules of low relative molecular mass (PAC, 1996, 68, 2291). The term“oligomer” generally means a molecule of intermediate relative molecularmass, the structure of which essentially comprises a small plurality ofunits derived, actually or conceptually, from molecules of lowerrelative molecular mass (PAC, 1996, 68, 2291). In a preferred senseaccording to the present invention a polymer means a compound having >1,preferably ≧5 repeating units, and an oligomer means a compound with >1and <10, preferably <5, repeating units.

The terms “repeating unit” and “monomeric unit” mean the constitutionalrepeating unit (CRU), which is the smallest constitutional unit therepetition of which constitutes a regular macromolecule, a regularoligomer molecule, a regular block or a regular chain (PAC, 1996, 68,2291).

The term “leaving group” means an atom or group (charged or uncharged)that becomes detached from an atom in what is considered to be theresidual or main part of the molecule taking part in a specifiedreaction (see also PAC, 1994, 66, 1134).

The term “conjugated” means a compound containing mainly C atoms withsp²-hybridisation (or optionally also sp-hybridisation), which may alsobe replaced by hetero atoms. In the simplest case this is for example acompound with alternating C—C single and double (or triple) bonds, butdoes also include compounds with units like 1,3-phenylene. “Mainly”means in this connection that a compound with naturally (spontaneously)occurring defects, which may lead to interruption of the conjugation, isstill regarded as a conjugated compound.

Unless stated otherwise, the molecular weight is given as the numberaverage molecular weight M_(n) or weight average molecular weight M_(W),which is determined by gel permeation chromatography (GPC) againstpolystyrene standards in eluent solvents such as tetrahydrofuran,chloroform, chlorobenzene or 1,2,4-trichlorobenzene. The degree ofpolymerization (n) means the number average degree of polymerizationgiven as n=M_(n)/M_(U), wherein M_(U) is the molecular weight of thesingle repeating unit as described in J. M. G. Cowie, Polymers:Chemistry & Physics of Modern Materials, Blackie, Glasgow, 1991.

The term “carbyl group” as used above and below denotes any monovalentor multivalent organic radical moiety which comprises at least onecarbon atom either without any non-carbon atoms (like for example—C≡C—), or optionally combined with at least one non-carbon atom such asN, O, S, P, Si, Se, As, Te or Ge (for example carbonyl etc.). The term“hydrocarbyl group” denotes a carbyl group that does additionallycontain one or more H atoms and optionally contains one or more heteroatoms like for example N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group comprising a chain of 3 or more C atomsmay also be straight-chain, branched and/or cyclic, including spiroand/or fused rings.

Preferred carbyl and hydrocarbyl groups include alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy,each of which is optionally substituted and has 1 to 40, preferably 1 to25, very preferably 1 to 18 C atoms, furthermore optionally substitutedaryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, furthermorealkylaryloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy andaryloxycarbonyloxy, each of which is optionally substituted and has 6 to40, preferably 7 to 40 C atoms, wherein all these groups do optionallycontain one or more hetero atoms, preferably selected from N, O, S, P,Si, Se, As, Te and Ge.

The carbyl or hydrocarbyl group may be a saturated or unsaturatedacyclic group, or a saturated or unsaturated cyclic group. Unsaturatedacyclic or cyclic groups are preferred, especially aryl, alkenyl andalkynyl groups (especially ethynyl). Where the C₁-C₄₀ carbyl orhydrocarbyl group is acyclic, the group may be straight-chain orbranched. The C₁-C₄₀ carbyl or hydrocarbyl group includes for example: aC₁-C₄₀ alkyl group, a C₁-C₄₀ alkoxy or oxaalkyl group, a C₂-C₄₀ alkenylgroup, a C₂-C₄₀ alkynyl group, a C₃-C₄₀ alkyl group, a C₄-C₄₀alkyldienyl group, a C₄-C₄₀ polyenyl group, a C₆-C₁₈ aryl group, aC₆-C₄₀ alkylaryl group, a C₆-C₄₀ arylalkyl group, a C₄-C₄₀ cycloalkylgroup, a C₄-C₄₀ cycloalkenyl group, and the like. Preferred among theforegoing groups are a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, aC₂-C₂₀ alkynyl group, a C₃-C₂₀ alkyl group, a C₄-C₂₀ alkyldienyl group,a C₆-C₁₂ aryl group, and a C₄-C₂₀ polyenyl group, respectively. Alsoincluded are combinations of groups having carbon atoms and groupshaving hetero atoms, like e.g. an alkynyl group, preferably ethynyl,that is substituted with a silyl group, preferably a trialkylsilylgroup.

Aryl and heteroaryl preferably denote a mono-, bi- or tricyclic aromaticor heteroaromatic group with 4 to 30 ring C atoms that may also comprisecondensed rings and is optionally substituted with one or more groups Las defined above.

Very preferred substituents L are selected from halogen, most preferablyF, or alkyl, alkoxy, oxaalkyl, thioalkyl, fluoroalkyl and fluoroalkoxywith 1 to 12 C atoms or alkenyl, alkynyl with 2 to 12 C atoms.

Especially preferred aryl and heteroaryl groups are phenyl in which, inaddition, one or more CH groups may be replaced by N, naphthalene,thiophene, selenophene, thienothiophene, dithienothiophene, fluorene andoxazole, all of which can be unsubstituted, mono- or polysubstitutedwith L as defined above. Very preferred rings are selected from pyrrole,preferably N-pyrrole, pyridine, preferably 2- or 3-pyridine, pyrimidine,thiophene preferably 2-thiophene, selenophene, preferably 2-selenophene,thieno[3,2-b]thiophene, thiazole, thiadiazole, oxazole and oxadiazole,especially preferably thiophene-2-yl, 5-substituted thiophene-2-yl orpyridine-3-yl, all of which can be unsubstituted, mono- orpolysubstituted with L as defined above.

An alkyl or alkoxy radical, i.e. where the terminal CH₂ group isreplaced by —O—, can be straight-chain or branched. It is preferablystraight-chain, has 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordinglyis preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl,ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, or octoxy,furthermore methyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy ortetradecoxy, for example.

An alkenyl group, wherein one or more CH₂ groups are replaced by —CH═CH—can be straight-chain or branched. It is preferably straight-chain, has2 to 10 C atoms and accordingly is preferably vinyl, prop-1-, orprop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl,hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- orhept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-,4-, 5-, 6-, 7- or non-8-enyl, dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- ordec-9-enyl.

Especially preferred alkenyl groups are C₂-C₇-1E-alkenyl,C₄-C₇-3E-alkenyl, C₅-C₇-4-alkenyl, C₆-C₇-5-alkenyl and C₇-6-alkenyl, inparticular C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl and C₅-C₇-4-alkenyl.Examples for particularly preferred alkenyl groups are vinyl,1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl,3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl,4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groupshaving up to 5 C atoms are generally preferred.

An oxaalkyl group, i.e. where one CH₂ group is replaced by —O—, ispreferably straight-chain 2-oxapropyl (=methoxymethyl),2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3-, or4-oxapentyl, 2-, 3-, 4-, or 5-oxahexyl, 2-, 3-, 4-, 5-, or 6-oxaheptyl,2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonylor 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl, for example. Oxaalkyl, i.e.where one CH₂ group is replaced by —O—, is preferably straight-chain2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl(=2-methoxyethyl), 2-, 3-, or 4-oxapentyl, 2-, 3-, 4-, or 5-oxahexyl,2-, 3-, 4-, 5-, or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-,3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-, 7-, 8- or9-oxadecyl, for example.

In an alkyl group wherein one CH₂ group is replaced by —O— and one by—C(O)—, these radicals are preferably neighboured. Accordingly theseradicals together form a carbonyloxy group —C(O)—O— or an oxycarbonylgroup —O—C(O)—. Preferably this group is straight-chain and has 2 to 6 Catoms. It is accordingly preferably acetyloxy, propionyloxy, butyryloxy,pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl,butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl,2-propionyloxy-ethyl, 2-butyryloxyethyl, 3-acetyloxypropyl,3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl,ethoxy-carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl,2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl,2-(propoxy-carbonyl)ethyl, 3-(methoxycarbonyl)propyl,3-(ethoxycarbonyl)propyl, 4-(methoxycarbonyl)-butyl.

An alkyl group wherein two or more CH₂ groups are replaced by —O— and/or—C(O)O— can be straight-chain or branched. It is preferablystraight-chain and has 3 to 12 C atoms. Accordingly it is preferablybis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl,4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl,7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl,10,10-bis-carboxy-decyl, bis-(methoxycarbonyl)-methyl,2,2-bis-(methoxycarbonyl)-ethyl, 3,3-bis-(methoxycarbonyl)-propyl,4,4-bis-(methoxycarbonyl)-butyl, 5,5-bis-(methoxycarbonyl)-pentyl,6,6-bis-(methoxycarbonyl)-hexyl, 7,7-bis-(methoxycarbonyl)-heptyl,8,8-bis-(methoxycarbonyl)-octyl, bis-(ethoxycarbonyl)-methyl,2,2-bis-(ethoxycarbonyl)-ethyl, 3,3-bis-(ethoxycarbonyl)-propyl,4,4-bis-(ethoxycarbonyl)-butyl, 5,5-bis-(ethoxycarbonyl)-hexyl.

A thioalkyl group, i.e where one CH₂ group is replaced by —S—, ispreferably straight-chain thiomethyl (—SCH₃), 1-thioethyl (—SCH₂CH₃),1-thiopropyl (=—SCH₂CH₂CH₃), 1-(thiobutyl), 1-(thiopentyl),1-(thiohexyl), 1-(thioheptyl), 1-(thiooctyl), 1-(thiononyl),1-(thiodecyl), 1-(thioundecyl) or 1-(thiododecyl), wherein preferablythe CH₂ group adjacent to the sp² hybridised vinyl carbon atom isreplaced.

A fluoroalkyl group is preferably straight-chain perfluoroalkylC_(i)F_(2i+1), wherein i is an integer from 1 to 15, in particular CF₃,C₂F₅, C₃F₇, C₄F₉, C₅F₁₁, C₆F₁₃, C₇F₁₅ or C₈F₁₇, very preferably C₆F₁₃.

The above-mentioned alkyl, alkoxy, alkenyl, oxaalkyl, thioalkyl,carbonyl and carbonyloxy groups can be achiral or chiral groups.Particularly preferred chiral groups are 2-butyl (=1-methylpropyl),2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl,2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy,2-methylpentoxy, 3-methylpentoxy, 2-ethyl-hexoxy, 1-methylhexoxy,2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methyl-pentyl, 4-methylhexyl,2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-meth-oxyoctoxy,6-methyloctoxy, 6-methyloctanoyloxy, 5-methylheptyloxy-carbonyl,2-methylbutyryloxy, 3-methylvaleroyloxy, 4-methylhexanoyloxy,2-chloropropionyloxy, 2-chloro-3-methylbutyryloxy,2-chloro-4-methyl-valeryl-oxy, 2-chloro-3-methylvaleryloxy,2-methyl-3-oxapentyl, 2-methyl-3-oxa-hexyl, 1-methoxypropyl-2-oxy,1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl-2-oxy,2-fluorooctyloxy, 2-fluorodecyloxy, 1,1,1-trifluoro-2-octyloxy,1,1,1-trifluoro-2-octyl, 2-fluoromethyloctyloxy for example. Verypreferred are 2-hexyl, 2-octyl, 2-octyloxy, 1,1,1-trifluoro-2-hexyl,1,1,1-trifluoro-2-octyl and 1,1,1-trifluoro-2-octyloxy.

Preferred achiral branched groups are isopropyl, isobutyl(=methylpropyl), isopentyl (=3-methylbutyl), tert. butyl, isopropoxy,2-methyl-propoxy and 3-methylbutoxy.

In another preferred embodiment of the present invention, R is selectedfrom primary, secondary or tertiary alkyl or alkoxy with 1 to 30 Catoms, wherein one or more H atoms are optionally replaced by F, oraryl, aryloxy, heteroaryl or heteroaryloxy that is optionally alkylatedor alkoxylated and has 4 to 30 ring atoms. Very preferred groups of thistype are selected from the group consisting of the following formulae

wherein “ALK” denotes optionally fluorinated, preferably linear, alkylor alkoxy with 1 to 20, preferably 1 to 12 C-atoms, in case of tertiarygroups very preferably 1 to 9 C atoms, and the dashed line denotes thelink to the ring to which these groups are attached. Especiallypreferred among these groups are those wherein all ALK subgroups areidentical.

—CY¹═CY²— is preferably —CH═CH—, —CF═CF— or —CH═C(CN)—.

Halogen is F, Cl, Br or I, preferably F, Cl or Br.

—CO—, —C(═O)— and —C(O)— denote a carbonyl group, i.e.

The polymers may also be substituted with a polymerisable orcrosslinkable reactive group, which is optionally protected during theprocess of forming the polymer. Particular preferred polymers of thistype are those of formula I wherein R¹ denotes P-Sp. These polymers areparticularly useful as semiconductors or charge transport materials, asthey can be crosslinked via the groups P, for example by polymerisationin situ, during or after processing the polymer into a thin film for asemiconductor component, to yield crosslinked polymer films with highcharge carrier mobility and high thermal, mechanical and chemicalstability.

Preferably the polymerisable or crosslinkable group P is selected fromCH₂═CW¹—C(O)—O—, CH₂═CW¹—C(O)—,

CH₂═CW²—(O)_(k1)—, CW¹═CH—C(O)—(O)_(k3)—, CW¹═CH—C(O)—NH—,CH₂═CW¹—C(O)—NH—, CH₃—CH═CH—O—, (CH₂═CH)₂CH—OC(O)—,(CH₂═CH—CH₂)₂CH—O—C(O)—, (CH₂═CH)₂CH—O—, (CH₂═CH—CH₂)₂N—,(CH₂═CH—CH₂)₂N—C(O)—, HO—CW²W³—, HS—CW²W³—, HW²N—, HO—CW²W³—NH—,CH₂═CH—(C(O)—O)_(k1)-Phe-(O)_(k2)—, CH₂═CH—(C(O))_(k1)-Phe-(O)_(k2)—,Phe-CH═CH—, HOOC—, OCN—, and W⁴W⁵W⁶Si—, with W¹ being H, F, Cl, CN, CF₃,phenyl or alkyl with 1 to 5 C-atoms, in particular H, Cl or CH₃, W² andW³ being independently of each other H or alkyl with 1 to 5 C-atoms, inparticular H, methyl, ethyl or n-propyl, W⁴, W⁵ and W⁶ beingindependently of each other Cl, oxaalkyl or oxacarbonylalkyl with 1 to 5C-atoms, W⁷ and W⁸ being independently of each other H, Cl or alkyl with1 to 5 C-atoms, Phe being 1,4-phenylene that is optionally substitutedby one or more groups L as defined above, k₁, k₂ and k₃ beingindependently of each other 0 or 1, k₃ preferably being 1, and k₄ beingan integer from 1 to 10.

Alternatively P is a protected derivative of these groups which isnon-reactive under the conditions described for the process according tothe present invention. Suitable protective groups are known to theordinary expert and described in the literature, for example in Green,“Protective Groups in Organic Synthesis”, John Wiley and Sons, New York(1981), like for example acetals or ketals.

Especially preferred groups P are CH₂═CH—C(O)—O—, CH₂═C(CH₃)—C(O)—O—,CH₂═CF—C(O)—O—, CH₂═CH—O—, (CH₂═CH)₂CH—O—C(O)—, (CH₂═CH)₂CH—O—,

or protected derivatives thereof. Further preferred groups P areselected from the group consisting of vinyloxy, acrylate, methacrylate,fluoroacrylate, chloracrylate, oxetan and epoxy groups, very preferablyfrom an acrylate or methacrylate group.

Polymerisation of group P can be carried out according to methods thatare known to the ordinary expert and described in the literature, forexample in D. J. Broer; G. Challa; G. N. Mol, Macromol. Chem., 1991,192, 59.

The term “spacer group” is known in prior art and suitable spacer groupsSp are known to the ordinary expert (see e.g. Pure Appl. Chem. 73(5),888 (2001). The spacer group Sp is preferably of formula Sp′-X′, suchthat P-Sp- is P-Sp′-X′-, wherein

-   Sp′ is alkylene with up to 30 C atoms which is unsubstituted or    mono- or polysubstituted by F, Cl, Br, I or CN, it being also    possible for one or more non-adjacent CH₂ groups to be replaced, in    each case independently from one another, by —O—, —S—, —NH—, —NR⁰—,    —SiR⁰R⁰⁰—, —C(O)—, —C(O)O—, —OC(O)—, —OC(O)—O—, —S—C(O)—, —C(O)—S—,    —CH═CH— or —C≡C— in such a manner that O and/or S atoms are not    linked directly to one another,-   X′ is —O—, —S—, —C(O)—, —C(O)O—, —OC(O)—, —O—C(O)O—, —C(O)—NR⁰—,    —NR⁰—C(O)—, —NR⁰—C(O)—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—,    —OCF₂—, —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—,    —N═CH—, —N═N—, —CH═CR⁰—, —CY¹═CY²—, —C≡C—, —CH═CH—C(O)O—,    —OC(O)—CH═CH— or a single bond,-   R⁰ and R⁰⁰ are independently of each other H or alkyl with 1 to 12    C-atoms, and-   Y¹ and Y² are independently of each other H, F, Cl or CN.

X′ is preferably —O—, —S—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—,—OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—,—N═CH—, —N═N—, —CH═CR⁰—, —CY¹═CY²—, —C≡C— or a single bond, inparticular —O—, —S—, —C≡C—, —CY¹═CY²— or a single bond. In anotherpreferred embodiment X′ is a group that is able to form a conjugatedsystem, such as —C≡C— or —CY¹═CY²—, or a single bond.

Typical groups Sp′ are, for example, —(CH₂)_(p)—,—(CH₂CH₂O)_(q)—CH₂CH₂—, —CH₂CH₂—S—CH₂CH₂— or —CH₂CH₂—NH—CH₂CH₂— or—(SiR⁰R⁰⁰—O)_(p)—, with p being an integer from 2 to 12, q being aninteger from 1 to 3 and R⁰ and R⁰⁰ having the meanings given above.

Preferred groups Sp′ are ethylene, propylene, butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene,dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene,ethylene-thioethylene, ethylene-N-methyl-iminoethylene,1-methylalkylene, ethenylene, propenylene and butenylene for example.

The polymers containing units of formula I, especially those of formulaII, are preferably selected of formula IIaR⁴—[(Ar¹—U—Ar²)_(x)—(Ar³)_(y)]_(n)—R⁵  IIawherein U, Ar¹⁻³, n, x and y have the meanings of formula I and II, and

-   R³ and R⁵ have independently of each other one of the meanings of    R³, preferably F, Br or Cl, or denote H, —CH₂Cl, —CHO, —CH═CH₂,    —SiR′R″R′″, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂, or P-Sp,    wherein P and Sp are as defined above, and R′, R″ and R′″ have    independently of each other one of the meanings of R⁰ defined above,    and two of R′, R″ and R′″ may also form a ring together with the    hetero atom to which they are attached.

In the polymers according to the present invention, the total number ofrepeating units n is preferably ≧5, very preferably ≧10, most preferably50, and preferably up to 500, very preferably up to 1,000, mostpreferably up to 2,000, including any combination of the aforementionedlower and upper limits of n.

The polymers of the present invention include homopolymers andcopolymers, like statistical or random copolymers, alternatingcopolymers and block copolymers, as well as combinations thereof.

Block copolymers may for example comprise or consist of one or moreblocks formed by units of formula I and one or more blocks formed byunits Ar³, wherein Ar³ has one of the meanings of formula II or asdescribed above and below.

Another aspect of the invention relates to monomers of formula IaR⁴—Ar¹—U—Ar²—R⁵  Iawherein U, Ar¹, Ar², R⁴ and R⁵ have the meanings of formula II and IIa,or one of the preferred meanings as described above and below.

Especially preferred are monomers of formula Ia wherein R⁴ and R⁵ are,preferably independently of each other, selected from the groupconsisting of Cl, Br, I, O-tosylate, O-triflate, O-mesylate,O-nonaflate, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂, —CZ³═C(Z³)₂, —C≡CHand —Sn(Z⁴)₃, wherein Z¹⁻⁴ are selected from the group consisting ofalkyl and aryl, each being optionally substituted, and two groups Z² mayalso form a cyclic group.

Preferably the repeating units of formula I, the monomers of formula Ia,and the polymers of formula II and IIa containing them, are selectedfrom the following list of preferred embodiments:

-   -   W is S,    -   W is Se,    -   W is O,    -   W is NR^(x),    -   E¹ is —O—C(O)— and E² is —C(O)—O, i.e. both ester groups are        attached to the benzene ring in formula I via the carbonyl        C-atom,    -   E¹ is —C(O)—O— and E² is O—C(O)—, i.e. both ester groups are        attached to the benzene ring in formula I via the O-atom,    -   one of Ar¹ and Ar² is a single bond,    -   both Ar¹ and Ar² are a single bond,    -   both Ar¹ and Ar² are not a single bond,    -   Ar¹ and Ar², when being different from a single bond, are        selected from the group consisting of thiophene-2,5-diyl,        thiazole-2,5-diyl, selenophene-2,5-diyl, furan-2,5-diyl,        thieno[3,2-b]thiophene-2,5-diyl,        thieno[2,3-b]thiophene-2,5-diyl,        selenopheno[3,2-b]selenophene-2,5-diyl,        selenopheno[2,3-b]selenophene-2,5-diyl,        selenopheno[3,2-b]thiophene-2,5-diyl, or        selenopheno[2,3-b]thiophene-2,5-diyl, all of which are        unsubstituted, or mono- or polysubstituted, preferably with R³        as defined above and below,    -   Ar³ is selected from the group consisting of 1,4-phenylene,        2,3-dicyano-1,4-phenylene, 2,5-dicyano,        2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene,        2,3,5,6-tetrafluoro, 3,4-difluorothiophene-2,5-diyl,        pyridine-2,5-diyl, pyrimidine-2,5-diyl, naphthalene-2,6-diyl,        thiophene-2,5-diyl, selenophene-2,5-diyl,        thieno[3,2-b]thiophene-2,5-diyl,        thieno[2,3-b]thiophene-2,5-diyl,        selenopheno[3,2-b]selenophene-2,5-diyl,        selenopheno[2,3-b]selenophene-2,5-diyl,        selenopheno[3,2-b]thiophene-2,5-diyl,        selenopheno[2,3-b]thiophene-2,5-diyl,        benzo[1,2-b:4,5-b′]di-thiophene-2,6-diyl, 2,2-dithiophene,        2,2-diselenophene, dithieno[3,2-b:2′,3′-d]silole-5,5-diyl,        dithieno[3,2-b;2′,3′-d]pyrrole-5,5-diyl,        4H-cyclopenta[2,1-b:3,4-b′]dithiophene-2,6-diyl,        carbazole-2,7-diyl, fluorene-2,7-diyl,        indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl,        benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b′]thiophene)-2,7-diyl,        phenanthro[1,10,9,8-c,d,e,f,g]carbazole-2,7-diyl,        benzo[2,1,3]thia-diazole-4,7-diyl,        benzo[2,1,3]selenadiazole-4,7-diyl,        benzo[2,1,3]oxa-diazole-4,7-diyl, 2H-benzotriazole-4,7-diyl,        3,4-difluorothiophene-2,5-diyl, quinoxaline-5,8-diyl,        thieno[3,4-b]pyrazine-2,5-diyl, thieno[3,4-b]thiophene-4,6-diyl,        thieno[3,4-b]thiophene-6,4-diyl,        3,6-di-thien-2-yl-pyrrolo[3,4-c]pyrrole-1,4-dione, or        [1,3]thiazolo[5,4-d][1,3]thiazole-2,5-diyl, all of which are        unsubstituted, or mono- or polysubstituted, preferably with R³        as defined above and below,    -   n is at least 5, preferably at least 10, very preferably at        least 50, and up to 2,000, preferably up to 500.    -   M_(w) is at least 5,000, preferably at least 8,000, very        preferably at least 10,000, and preferably up to 300,000, very        preferably up to 100,000,    -   R¹ and R² are selected from the group consisting of primary        alkyl or alkoxy with 1 to 30 C atoms, secondary alkyl or alkoxy        with 3 to 30 C atoms, and tertiary alkyl or alkoxy with 4 to 30        C atoms, wherein in all these groups one or more H atoms are        optionally replaced by F,    -   R¹ and R² are selected from the group consisting of aryl,        heteroaryl, aryloxy, heteroaryloxy, each of which is optionally        alkylated or alkoxylated and has 4 to 30 ring atoms,    -   R³ is F, Cl, Br, I, CN, R⁶, —C(O)—R⁶, —C(O)—O—R⁶, or —O—C(O)—R⁶,        wherein R⁶ is straight-chain, branched or cyclic alkyl with 1 to        30 C atoms, in which one or more non-adjacent C atoms are        optionally replaced by —O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—,        —O—C(O)—O—, —CR⁰═CR⁰⁰— or —C≡C— and in which one or more H atoms        are optionally replaced by F, Cl, Br, I or CN, or R³ is aryl,        aryloxy, heteroaryl or heteroaryloxy having 4 to 30 ring atoms        which is unsubstituted or which is substituted by one or more        halogen atoms or by one or more groups R⁶, —C(O)—R⁶, —C(O)—O—R⁶,        or —O—C(O)—R⁶ as defined above,    -   R⁶ is primary alkyl with 1 to 30 C atoms, very preferably with 1        to 15 C atoms, secondary alkyl with 3 to 30 C atoms, or tertiary        alkyl with 4 to 30 C atoms, wherein in all these groups one or        more H atoms are optionally replaced by F,    -   R⁰ and R⁰⁰ are selected from H or C₁-C₁₀-alkyl,    -   R⁴ and R⁵ are selected from H, halogen, —CH₂Cl, —CHO,        —CH═CH₂—SiR′R″R″′, —SnR′R″R″′, —BR′R″, —B(OR′)(OR″), —B(OH)₂,        P-Sp, C₁-C₂₀-alkyl, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyl,        C₁-C₂₀-fluoroalkyl and optionally substituted aryl or        heteroaryl,    -   R⁴ and R⁵ are, preferably independently of each other, selected        from the group consisting of Cl, Br, I, O-tosylate, O-triflate,        O-mesylate, O-nonaflate, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂,        —CZ³═C(Z⁴)₂, —C≡CH and —Sn(Z⁴)₃, wherein Z¹⁻⁴ are selected from        the group consisting of alkyl and aryl, each being optionally        substituted, and two groups Z² may also form a cyclic group,        very preferably from Br,    -   R^(x) is H, alkyl, alkoxy, alkylcarbonyl, alkylcarbonyloxy or        alkoxycarbonyl with 1 to 30 C atoms, wherein one or more H atoms        are optionally replaced by F.

Preferred polymers of formula II are selected from the group consistingof the following formulae:

wherein Ar denotes a group of formula 1, 2 or 3

-   X is C(R^(x)) or N,-   Y is O, S, Se or N(R^(x)),-   Z is C(R^(x)) or N,-   Y¹ is O, S, Se, N(R^(x)), or —CH═CH—,-   Z¹ is C(R^(x)) or N,-   W and R^(x) have the meanings of formula I or one of the preferred    meanings given above and below,-   U¹ and U² are each, independently of one another, —C(R^(x))═,    —C(R^(x)R^(y))—, —S(iR^(x)R^(y))—, —N(R^(x))—, —S—, —Se—, —O— or a    single bond, wherein U¹ and U² are not both a single bond,-   R^(y) has one of the meanings given for R^(x),-   u is 0 or 1,-   n has the meaning of formula II or one of the preferred meanings    given above and below.

Especially preferred are polymers of formulae IIA-IID wherein W is S.Further preferred are polymers of formulae IIA-IID, wherein X and Z areC(R^(x)) and Y is S or Se, most preferably S.

Further preferred are polymers of formulae IIA-IID, wherein Ar is agroup of formula 1 or 2 in which u is 1, in particular those selectedfrom the following groups:

-   -   the group consisting of polymers wherein Z is C(R^(x)) and Y is        S or Se, very preferably S, and/or wherein W is S,    -   the group consisting of polymers wherein U¹ and U² are        —C(R^(x))═,    -   the group consisting of polymers wherein one of U¹ and U² is a        single bond and the other is —C(R^(x)R^(y))—, —S(iR^(x)R^(y))—        or —N(R^(x))—,    -   the group consisting of polymers wherein Ar is of formula 1, U¹        is a single bond and U² is —C(R^(x)R^(y))—, —S(iR^(x)R^(y))— or        —N(R^(x))—, very preferably wherein X, Z and Z¹ denote C(Rx) and        Y and Y¹ denote S or Se, most preferably S,    -   the group consisting of polymers wherein Ar is formula 1, Y¹ is        —CH═CH— and Z¹ is C(R^(x)), and preferably X and Z are C(R^(x))        and Y is S or Se, most preferably S,    -   the group consisting of polymers wherein Ar is of formula 1, Y¹        is —CH═CH—, Z¹ is C(R^(x)), U¹ is a single bond, and U² is        —C(R^(x)R^(y))—, —S(iR^(x)R^(y))— or —N(R^(x))—, and preferably        wherein X and Z are C(R^(x)) and Y is S or Se, most preferably        S,    -   the group consisting of polymers wherein Ar is of formula 2, U¹        and U² are —C(R^(x))═, and preferably wherein X, Z and Z¹ denote        C(Rx) and Y and Y¹ denote S or Se, most preferably S.

Further preferred are polymers of formulae IIA-IID, wherein Ar is agroup of formula 1 or 2 in which u is 0, very preferably wherein X, Zand Z¹ denote C(R^(x)) and Y and Y¹ denote S or Se, most preferably S.

Further preferred are polymers of formulae IIA-IID, preferably those offormula IIC or IID, wherein Ar is a group of formula 3, X and Z areC(R^(x)) and Y is S or Se, very preferably S.

Very preferred polymers of formulae II and IIA-IID are selected from thegroup consisting of the following formulae:

wherein R¹, R², R^(x), R^(y) and n have the meanings as given in formulaI, II and IIA, or one of the preferred meanings given above and below.

Preferred polymers of formula IIa are selected of the formulaR⁴-chain-R⁵wherein “chain” is a polymer chain selected from above formulae IIA-IIDand II1-15, and R⁴ and R⁵ have one of the meanings given in formula IIaor one of the preferred meanings given above and below.

The polymers of the present invention can be synthesized according to orin analogy to methods that are known to the skilled person and aredescribed in the literature. Other methods of preparation can be takenfrom the examples. For example, they can be suitably prepared byaryl-aryl coupling reactions, such as Yamamoto coupling, Suzukicoupling, Stille coupling, Sonogashira coupling, Heck coupling orBuchwald coupling. Suzuki coupling and Yamamoto coupling are especiallypreferred.

The monomers which are polymerised to form the repeat units of thepolymers can be prepared according to methods which are known to theperson skilled in the art.

Preferably the polymers are prepared from monomers of formula Ia or itspreferred embodiments as described above and below.

Another aspect of the invention is a process for preparing a polymer bycoupling one or more identical or different monomeric units of formula Ior monomers of formula Ia with each other and/or with one or morecomonomers in a polymerisation reaction, preferably in an aryl-arylcoupling reaction.

Suitable and preferred comonomers are those of the formulaR⁴—Ar³—R⁵wherein R⁴ and R⁵ have one of the meanings of formula IIa or one of thepreferred meanings given above and below, and Ar³ has one of themeanings of formula IIa or of Ar in formula IIa, or one of the preferredmeanings given above and below.

Preferred methods for polymerisation are those leading to C—C-couplingor C—N-coupling, like Suzuki polymerisation, as described for example inWO 00/53656, Yamamoto polymerisation, as described in for example in T.Yamamoto et al., Progress in Polymer Science 1993, 17, 1153-1205 or inWO 2004/022626 A1, and Stille coupling. For example, when synthesizing alinear polymer by Yamamoto polymerisation, monomers as described abovehaving two reactive halide groups R² and R³ is preferably used. Whensynthesizing a linear polymer by Suzuki polymerisation, preferably amonomer as described above is used wherein at least one reactive groupR² or R³ is a boronic acid or boronic acid derivative group.

Suzuki polymerisation may be used to prepare homopolymers as well asstatistical, alternating and block random copolymers. Statistical orblock copolymers can be prepared for example from the above monomers offormula Ia wherein one of the reactive groups R² and R³ is halogen andthe other reactive group is a boronic acid or boronic acid derivativegroup. The synthesis of statistical, alternating and block copolymers isdescribed in detail for example in WO 03/048225 A2 or WO 2005/014688 A2.

Suzuki polymerisation employs a Pd(0) complex or a Pd(II) salt.Preferred Pd(0) complexes are those bearing at least one phosphineligand such as Pd(Ph₃P)₄. Another preferred phosphine ligand istris(ortho-tolyl)phosphine, i.e. Pd(o-Tol)₄. Preferred Pd(II) saltsinclude palladium acetate, i.e. Pd(OAc)₂. Suzuki polymerisation isperformed in the presence of a base, for example sodium carbonate,potassium phosphate or an organic base such as tetraethylammoniumcarbonate. Yamamoto polymerisation employs a Ni(0) complex, for examplebis(1,5-cyclooctadienyl) nickel(0).

As alternatives to halogens as described above, leaving groups offormula —O—SO₂Z¹ can be used wherein Z¹ is as described above.Particular examples of such leaving groups are tosylate, mesylate andtriflate.

Especially suitable and preferred synthesis methods of the repeatingunits and monomers of formula I and Ia, and their homo- and co-polymersof formula II and IIa, are illustrated in the synthesis schemes shownhereinafter, wherein R, Ar¹, Ar² and Ar³ are as defined in formula I andII.

A synthesis scheme for the preparation of4,7-dibromo-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acid bis-ester and4,7-bis-(5-bromo-thiophen-2-yl)-benzo[2,1,3]thiadiazole-5,6-dicarboxylicacid bis-ester is shown in Scheme 1 (see C. Burmester, R. Faust,Synthesis, 2008, 8, 1179, and WO2010031479 A1).

Synthesis schemes for the co-polymerisation of4,7-dibromo-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acid bis-ester and4,7-bis-(5-bromo-thiophen-2-yl)-benzo[2,1,3]thiadiazole-5,6-dicarboxylicacid bis-ester are shown in Scheme 2 (alternating copolymers) and Scheme3 (random copolymer).

The novel methods of preparing monomers and polymers as described aboveand below are another aspect of the invention.

The polymers according to the present invention can also be used inmixtures or polymer blends, for example together with monomericcompounds or together with other polymers having charge-transport,semiconducting, electrically conducting, photoconducting and/or lightemitting semiconducting properties, or for example with polymers havinghole blocking or electron blocking properties for use as interlayers orcharge blocking layers in OLED devices. Thus, another aspect of theinvention relates to a polymer blend comprising one or more polymersaccording to the present invention and one or more further polymershaving one or more of the above-mentioned properties. These blends canbe prepared by conventional methods that are described in prior art andknown to the skilled person. Typically the polymers are mixed with eachother or dissolved in suitable solvents and the solutions combined.

Another aspect of the invention relates to a formulation comprising oneor more polymers, mixtures or polymer blends as described above andbelow and one or more organic solvents.

Preferred solvents are aliphatic hydrocarbons, chlorinated hydrocarbons,aromatic hydrocarbons, ketones, ethers and mixtures thereof. Additionalsolvents which can be used include 1,2,4-trimethylbenzene,1,2,3,4-tetramethyl benzene, pentylbenzene, mesitylene, cumene, cymene,cyclohexylbenzene, diethylbenzene, tetralin, decalin, 2,6-lutidine,2-fluoro-m-xylene, 3-fluoro-o-xylene, 2-chlorobenzotrifluoride,dimethylformamide, 2-chloro-6-fluorotoluene, 2-fluoroanisole, anisole,2,3-dimethylpyrazine, 4-fluoroanisole, 3-fluoroanisole,3-trifluoro-methylanisole, 2-methylanisole, phenetol, 4-methylanisole,3-methylanisole, 4-fluoro-3-methylanisole, 2-fluorobenzonitrile,4-fluoroveratrol, 2,6-dimethylanisole, 3-fluorobenzonitrile,2,5-dimethylanisole, 2,4-dimethylanisole, benzonitrile,3,5-dimethylanisole, N,N-dimethylaniline, ethyl benzoate,1-fluoro-3,5-dimethoxybenzene, 1-methylnaphthalene,N-methylpyrrolidinone, 3-fluorobenzotrifluoride, benzotrifluoride,benzotrifluoride, diosane, trifluoromethoxybenzene,4-fluorobenzotrifluoride, 3-fluoropyridine, toluene, 2-fluorotoluene,2-fluorobenzotrifluoride, 3-fluorotoluene, 4-isopropylbiphenyl, phenylether, pyridine, 4-fluorotoluene, 2,5-difluorotoluene,1-chloro-2,4-difluorobenzene, 2-fluoropyridine, 3-chlorofluorobenzene,3-chlorofluorobenzene, 1-chloro-2,5-difluorobenzene,4-chlorofluorobenzene, chlorobenzene, o-dichlorobenzene,2-chlorofluorobenzene, p-xylene, m-xylene, o-xylene or mixture of o-,m-, and p-isomers. Solvents with relatively low polarity are generallypreferred. For inkjet printing solvents with high boiling temperaturesand solvent mixtures are preferred. For spin coating alkylated benzeneslike xylene and toluene are preferred.

Examples of especially preferred solvents include, without limitation,dichloromethane, trichloromethane, monochlorobenzene, o-dichlorobenzene,tetrahydrofuran, anisole, morpholine, toluene, o-xylene, m-xylene,p-xylene, 1,4-dioxane, acetone, methylethylketone, 1,2-dichloroethane,1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, ethyl acetate, n-butylacetate, dimethylformamide, dimethylacetamide, dimethylsulfoxide,tetraline, decaline, indane, methyl benzoate, ethyl benzoate, mesityleneand/or mixtures thereof.

The concentration of the polymers in the solution is preferably 0.1 to10% by weight, more preferably 0.5 to 5% by weight. Optionally, thesolution also comprises one or more binders to adjust the rheologicalproperties, as described for example in WO 2005/055248 A1.

After the appropriate mixing and ageing, solutions are evaluated as oneof the following categories: complete solution, borderline solution orinsoluble. The contour line is drawn to outline the solubilityparameter-hydrogen bonding limits dividing solubility and insolubility.‘Complete’ solvents falling within the solubility area can be chosenfrom literature values such as published in “Crowley, J. D., Teague, G.S. Jr and Lowe, J. W. Jr., Journal of Paint Technology, 38, No 496, 296(1966)”. Solvent blends may also be used and can be identified asdescribed in “Solvents, W. H. Ellis, Federation of Societies forCoatings Technology, p 9-10, 1986”. Such a procedure may lead to a blendof ‘non’ solvents that will dissolve both the polymers of the presentinvention, although it is desirable to have at least one true solvent ina blend.

The polymers according to the present invention can also be used inpatterned OSC layers in the devices as described above and below. Forapplications in modern microelectronics it is generally desirable togenerate small structures or patterns to reduce cost (more devices/unitarea), and power consumption. Patterning of thin layers comprising apolymer according to the present invention can be carried out forexample by photolithography, electron beam lithography or laserpatterning.

For use as thin layers in electronic or electrooptical devices thepolymers, polymer blends or formulations of the present invention may bedeposited by any suitable method. Liquid coating of devices is moredesirable than vacuum deposition techniques. Solution deposition methodsare especially preferred. The formulations of the present inventionenable the use of a number of liquid coating techniques. Preferreddeposition techniques include, without limitation, dip coating, spincoating, ink jet printing, letter-press printing, screen printing,doctor blade coating, roller printing, reverse-roller printing, offsetlithography printing, flexographic printing, web printing, spraycoating, brush coating or pad printing. Ink-jet printing is particularlypreferred as it allows high resolution layers and devices to beprepared.

Selected formulations of the present invention may be applied toprefabricated device substrates by ink jet printing or microdispensing.Preferably industrial piezoelectric print heads such as but not limitedto those supplied by Aprion, Hitachi-Koki, InkJet Technology, On TargetTechnology, Picojet, Spectra, Trident, Xaar may be used to apply theorganic semiconductor layer to a substrate. Additionally semi-industrialheads such as those manufactured by Brother, Epson, Konica, SeikoInstruments Toshiba TEC or single nozzle microdispensers such as thoseproduced by Microdrop and Microfab may be used.

In order to be applied by ink jet printing or microdispensing, thepolymers should be first dissolved in a suitable solvent. Solvents mustfulfil the requirements stated above and must not have any detrimentaleffect on the chosen print head. Additionally, solvents should haveboiling points >100° C., preferably >140° C. and more preferably >150°C. in order to prevent operability problems caused by the solutiondrying out inside the print head. Apart from the solvents methonedabove, suitable solvents include substituted and non-substituted xylenederivatives, di-C₁₋₂-alkyl formamide, substituted and non-substitutedanisoles and other phenol-ether derivatives, substituted heterocyclessuch as substituted pyridines, pyrazines, pyrimidines, pyrrolidinones,substituted and non-substituted N,N-di-C₁₋₂-alkylanilines and otherfluorinated or chlorinated aromatics.

A preferred solvent for depositing a polymer according to the presentinvention by ink jet printing comprises a benzene derivative which has abenzene ring substituted by one or more substituents wherein the totalnumber of carbon atoms among the one or more substituents is at leastthree. For example, the benzene derivative may be substituted with apropyl group or three methyl groups, in either case there being at leastthree carbon atoms in total. Such a solvent enables an ink jet fluid tobe formed comprising the solvent with the polymer, which reduces orprevents clogging of the jets and separation of the components duringspraying. The solvent(s) may include those selected from the followinglist of examples: dodecylbenzene, 1-methyl-4-tert-butylbenzene,terpineol limonene, isodurene, terpinolene, cymene, diethylbenzene. Thesolvent may be a solvent mixture, that is a combination of two or moresolvents, each solvent preferably having a boiling point >100° C., morepreferably >140° C. Such solvent(s) also enhance film formation in thelayer deposited and reduce defects in the layer.

The ink jet fluid (that is mixture of solvent, binder and semiconductingcompound) preferably has a viscosity at 20° C. of 1-100 mPa·s, morepreferably 1-50 mPa·s and most preferably 1-30 mPa·s.

The polymers or formulations according to the present invention canadditionally comprise one or more further components or additivesselected for example from surface-active compounds, lubricating agents,wetting agents, dispersing agents, hydrophobing agents, adhesive agents,flow improvers, defoaming agents, deaerators, diluents which may bereactive or non-reactive, auxiliaries, colourants, dyes or pigments,sensitizers, stabilizers, nanoparticles or inhibitors.

The polymers according to the present invention are useful as chargetransport, semiconducting, electrically conducting, photoconducting orlight mitting materials in optical, electrooptical, electronic,electroluminescent or photoluminescent components or devices. In thesedevices, the polymers of the present invention are typically applied asthin layers or films.

Thus, the present invention also provides the use of the semiconductingpolymer, polymer blend, formulation or layer in an electronic device.The formulation may be used as a high mobility semiconducting materialin various devices and apparatus. The formulation may be used, forexample, in the form of a semiconducting layer or film. Accordingly, inanother aspect, the present invention provides a semiconducting layerfor use in an electronic device, the layer comprising a polymer, polymerblend or formulation according to the invention. The layer or film maybe less than about 30 microns. For various electronic deviceapplications, the thickness may be less than about 1 micron thick. Thelayer may be deposited, for example on a part of an electronic device,by any of the aforementioned solution coating or printing techniques.

The invention additionally provides an electronic device comprising apolymer, polymer blend, formulation or organic semiconducting layeraccording to the present invention. Especially preferred devices areOFETs, TFTs, ICs, logic circuits, capacitors, RFID tags, OLEDs, OLETs,OPEDs, OPVs, solar cells, laser diodes, photoconductors, photodetectors,electrophotographic devices, electrophotographic recording devices,organic memory devices, sensor devices, charge injection layers,Schottky diodes, planarising layers, antistatic films, conductingsubstrates and conducting patterns.

Especially preferred electronic device are OFETs, OLEDs and OPV devices,in particular bulk heterojunction (BHJ) OPV devices. In an OFET, forexample, the active semiconductor channel between the drain and sourcemay comprise the layer of the invention. As another example, in an OLEDdevice, the charge (hole or electron) injection or transport layer maycomprise the layer of the invention.

For use in OPV devices the polymer according to the present invention ispreferably used in a formulation that comprises or contains, morepreferably consists essentially of, very preferably exclusively of, ap-type (electron donor) semiconductor and an n-type (electron acceptor)semiconductor. The p-type semiconductor is constituted by a polymeraccording to the present invention. The n-type semiconductor can be aninorganic material such as zinc oxide or cadmium selenide, or an organicmaterial such as a fullerene derivate, for example (6,6)-phenylC61-butyric acid methyl ester, also known as “PCBM” or “PC₆₁BM”, asdisclosed for example in G. Yu, J. Gao, J. C. Hummelen, F. Wudl, A. J.Heeger, Science 1995, Vol. 270, p. 1789 ff and having the structureshown below, or an structural analogous compound with e.g. a C₇₁fullerene group (PC₇₁BM), or a polymer (see for example Coakley, K. M.and McGehee, M. D. Chem. Mater. 2004, 16, 4533).

A preferred material of this type is a blend or mixture of a polymeraccording to the present invention with a C₆₀ or C₇₀ fullerene ormodified C₆₀ fullerene like PC₆₁BM or PC₇₁BM. Preferably the ratiopolymer:fullerene is from 2:1 to 1:2 by weight, more preferably from1.2:1 to 1:1.2 by weight, most preferably 1:1 by weight. For the blendedmixture, an optional annealing step may be necessary to optimize blendmorpohology and consequently OPV device performance.

The OPV device can for example be of any type known from the literature[see e.g. Waldauf et al., Appl. Phys. Lett. 89, 233517 (2006)].

A first preferred OPV device according to the invention comprises:

-   -   a low work function electrode (11) (for example a metal, such as        aluminum), and a high work function electrode (12) (for example        ITO), one of which is transparent,    -   a layer (13) (also referred to as “active layer”) comprising a        hole transporting material and an electron transporting        material, preferably selected from OSC materials, situated        between the electrodes (11,12); the active layer can exist for        example as a bilayer or two distinct layers or blend or mixture        of p-type and n-type semiconductor, forming a bulk heterjunction        (BHJ) (see for example Coakley, K. M. and McGehee, M. D. Chem.        Mater. 2004, 16, 4533),    -   an optional conducting polymer layer (14), for example        comprising a blend of PEDOT:PSS        (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)),        situated between the active layer (13) and the high work        function electrode (12), to modify the work function of the high        work function electrode to provide an ohmic contact for holes,    -   an optional coating (15) (for example of LiF) on the side of the        low workfunction electrode (11) facing the active layer (13), to        provide an ohmic contact for electrons.

A second preferred OPV device according to the invention is an invertedOPV device and comprises:

-   -   a low work function electrode (21) (for example a metal, such as        gold), and a high work function electrode (22) (for example        ITO), one of which is transparent,    -   a layer (23) (also referred to as “active layer”) comprising a        hole transporting material and an electron transporting        material, preferably selected from OSC materials, situated        between the electrodes (21, 22); the active layer can exist for        example as a bilayer or two distinct layers or blend or mixture        of p-type and n-type semiconductor, forming a BHJ,    -   an optional conducting polymer layer (24), for example        comprising a blend of PEDOT:PSS, situated between the active        layer (23) and the low work function electrode (21) to provide        an ohmic contact for electrons,    -   an optional coating (25) (for example of TiO_(x)) on the side of        the high workfunction electrode (22) facing the active layer        (23), to provide an ohmic contact for holes.

In the OPV devices of the present invent invention the p-type and n-typesemiconductor materials are preferably selected from the materials, likethe polymer/fullerene systems, as described above. If the bilayer is ablend an optional annealing step may be necessary to optimize deviceperformance.

The compound, formulation and layer of the present invention are alsosuitable for use in an OFET as the semiconducting channel. Accordingly,the invention also provides an OFET comprising a gate electrode, aninsulating (or gate insulator) layer, a source electrode, a drainelectrode and an organic semiconducting channel connecting the sourceand drain electrodes, wherein the organic semiconducting channelcomprises a polymer, polymer blend, formulation or organicsemiconducting layer according to the present invention. Other featuresof the OFET are well known to those skilled in the art.

OFETs where an OSC material is arranged as a thin film between a gatedielectric and a drain and a source electrode, are generally known, andare described for example in U.S. Pat. No. 5,892,244, U.S. Pat. No.5,998,804, U.S. Pat. No. 6,723,394 and in the references cited in thebackground section. Due to the advantages, like low cost productionusing the solubility properties of the compounds according to theinvention and thus the processibility of large surfaces, preferredapplications of these FETs are such as integrated circuitry, TFTdisplays and security applications.

The gate, source and drain electrodes and the insulating andsemiconducting layer in the OFET device may be arranged in any sequence,provided that the source and drain electrode are separated from the gateelectrode by the insulating layer, the gate electrode and thesemiconductor layer both contact the insulating layer, and the sourceelectrode and the drain electrode both contact the semiconducting layer.

An OFET device according to the present invention preferably comprises:

-   -   a source electrode,    -   a drain electrode,    -   a gate electrode,    -   a semiconducting layer,    -   one or more gate insulator layers,    -   optionally a substrate.        wherein the semiconductor layer preferably comprises a polymer,        polymer blend or formulation as described above and below.

The OFET device can be a top gate device or a bottom gate device.Suitable structures and manufacturing methods of an OFET device areknown to the skilled in the art and are described in the literature, forexample in US 2007/0102696 A1.

The gate insulator layer preferably comprises a fluoropolymer, like e.g.the commercially available Cytop 809M® or Cytop 107M® (from AsahiGlass). Preferably the gate insulator layer is deposited, e.g. byspin-coating, doctor blading, wire bar coating, spray or dip coating orother known methods, from a formulation comprising an insulator materialand one or more solvents with one or more fluoro atoms (fluorosolvents),preferably a perfluorosolvent. A suitable perfluorosolvent is e.g. FC75®(available from Acros, catalogue number 12380). Other suitablefluoropolymers and fluorosolvents are known in prior art, like forexample the perfluoropolymers Teflon AF® 1600 or 2400 (from DuPont) orFluoropel® (from Cytonix) or the perfluorosolvent FC 43® (Acros, No.12377). Especially preferred are organic dielectric materials having alow permittivity (or dielectric constant) from 1.0 to 5.0, verypreferably from 1.8 to 4.0 (“low k materials”), as disclosed for examplein US 2007/0102696 A1 or U.S. Pat. No. 7,095,044.

In security applications, OFETs and other devices with semiconductingmaterials according to the present invention, like transistors ordiodes, can be used for RFID tags or security markings to authenticateand prevent counterfeiting of documents of value like banknotes, creditcards or ID cards, national ID documents, licenses or any product withmonetry value, like stamps, tickets, shares, cheques etc.

Alternatively, the materials according to the invention can be used inOLEDs, e.g. as the active display material in a flat panel displayapplications, or as backlight of a flat panel display like e.g. a liquidcrystal display. Common OLEDs are realized using multilayer structures.An emission layer is generally sandwiched between one or moreelectron-transport and/or hole-transport layers. By applying an electricvoltage electrons and holes as charge carriers move towards the emissionlayer where their recombination leads to the excitation and henceluminescence of the lumophor units contained in the emission layer. Theinventive compounds, materials and films may be employed in one or moreof the charge transport layers and/or in the emission layer,corresponding to their electrical and/or optical properties. Furthermoretheir use within the emission layer is especially advantageous, if thecompounds, materials and films according to the invention showelectroluminescent properties themselves or comprise electroluminescentgroups or compounds. The selection, characterization as well as theprocessing of suitable monomeric, oligomeric and polymeric compounds ormaterials for the use in OLEDs is generally known by a person skilled inthe art, see, e.g., Meerholz, Synthetic Materials, 111-112, 2000, 31-34,Alcala, J. Appl. Phys., 88, 2000, 7124-7128 and the literature citedtherein.

According to another use, the materials according to this invention,especially those showing photoluminescent properties, may be employed asmaterials of light sources, e.g. in display devices, as described in EP0 889 350 A1 or by C. Weder et al., Science, 279, 1998, 835-837.

A further aspect of the invention relates to both the oxidised andreduced form of the compounds according to this invention. Either lossor gain of electrons results in formation of a highly delocalised ionicform, which is of high conductivity. This can occur on exposure tocommon dopants. Suitable dopants and methods of doping are known tothose skilled in the art, e.g. from EP 0 528 662, U.S. Pat. No.5,198,153 or WO 96/21659.

The doping process typically implies treatment of the semiconductormaterial with an oxidating or reducing agent in a redox reaction to formdelocalised ionic centres in the material, with the correspondingcounterions derived from the applied dopants. Suitable doping methodscomprise for example exposure to a doping vapor in the atmosphericpressure or at a reduced pressure, electrochemical doping in a solutioncontaining a dopant, bringing a dopant into contact with thesemiconductor material to be thermally diffused, and ion-implantation ofthe dopant into the semiconductor material.

When electrons are used as carriers, suitable dopants are for examplehalogens (e.g., I₂, Cl₂, Br₂, ICl, ICl₃, IBr and IF), Lewis acids (e.g.,PF₅, AsF₅, SbF₅, BF₃, BCl₃, SbCl₅, BBr₃ and SO₃), protonic acids,organic acids, or amino acids (e.g., HF, HCl, HNO₃, H₂SO₄, HClO₄, FSO₃Hand ClSO₃H), transition metal compounds (e.g., FeCl₃, FeOCl, Fe(ClO₄)₃,Fe(4-CH₃C₆H₄SO₃)₃, TiCl₄, ZrCl₄, HfCl₄, NbF₅, NbCl₅, TaCl₅, MoF₅, MoCl₅,WF₅, WCl₆, UF₆ and LnCl₃ (wherein Ln is a lanthanoid), anions (e.g.,Cl⁻, Br⁻, I⁻, I₃ ⁻, HSO₄ ⁻, SO₄ ²⁻, NO₃ ⁻, ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻,SbF₆ ⁻, FeCl₄ ⁻, Fe(CN)₆ ³⁻, and anions of various sulfonic acids, suchas aryl-SO₃ ⁻). When holes are used as carriers, examples of dopants arecations (e.g., H⁺, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺), alkali metals (e.g., Li,Na, K, Rb, and Cs), alkaline-earth metals (e.g., Ca, Sr, and Ba), O₂,XeOF₄, (NO₂ ⁺) (SbF₆ ⁻), (NO₂ ⁺) (SbCl₆ ⁻), (NO₂ ⁺) (BF₄ ⁻), AgClO₄,H₂IrCl₆, La(NO₃)₃.6H₂O, FSO₂OOSO₂F, Eu, acetylcholine, R₄N⁺, (R is analkyl group), R₄P⁺ (R is an alkyl group), R₆As⁺ (R is an alkyl group),and R₃S⁺ (R is an alkyl group).

The conducting form of the compounds of the present invention can beused as an organic “metal” in applications including, but not limitedto, charge injection layers and ITO planarising layers in OLEDapplications, films for flat panel displays and touch screens,antistatic films, printed conductive substrates, patterns or tracts inelectronic applications such as printed circuit boards and condensers.

The compounds and formulations according to the present invention mayalso be suitable for use in organic plasmon-emitting diodes (OPEDs), asdescribed for example in Koller et al., Nature Photonics 2008 (publishedonline Sep. 28, 2008).

According to another use, the materials according to the presentinvention can be used alone or together with other materials in or asalignment layers in LCD or OLED devices, as described for example in US2003/0021913. The use of charge transport compounds according to thepresent invention can increase the electrical conductivity of thealignment layer. When used in an LCD, this increased electricalconductivity can reduce adverse residual dc effects in the switchableLCD cell and suppress image sticking or, for example in ferroelectricLCDs, reduce the residual charge produced by the switching of thespontaneous polarisation charge of the ferroelectric LCs. When used inan OLED device comprising a light emitting material provided onto thealignment layer, this increased electrical conductivity can enhance theelectroluminescence of the light emitting material. The compounds ormaterials according to the present invention having mesogenic or liquidcrystalline properties can form oriented anisotropic films as describedabove, which are especially useful as alignment layers to induce orenhance alignment in a liquid crystal medium provided onto saidanisotropic film. The materials according to the present invention mayalso be combined with photoisomerisable compounds and/or chromophoresfor use in or as photoalignment layers, as described in US 2003/0021913.

According to another use the materials according to the presentinvention, especially their water-soluble derivatives (for example withpolar or ionic side groups) or ionically doped forms, can be employed aschemical sensors or materials for detecting and discriminating DNAsequences. Such uses are described for example in L. Chen, D. W.McBranch, H. Wang, R. Helgeson, F. Wudl and D. G. Whitten, Proc. Natl.Acad. Sci. U.S.A. 1999, 96, 12287; D. Wang, X. Gong, P. S. Heeger, F.Rininsland, G. C. Bazan and A. J. Heeger, Proc. Natl. Acad. Sci. U.S.A.2002, 99, 49; N. DiCesare, M. R. Pinot, K. S. Schanze and J. R.Lakowicz, Langmuir 2002, 18, 7785; D. T. McQuade, A. E. Pullen, T. M.Swager, Chem. Rev. 2000, 100, 2537.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Each feature disclosed in this specification, unless statedotherwise, may be replaced by alternative features serving the same,equivalent or similar purpose. Thus, unless stated otherwise, eachfeature disclosed is one example only of a generic series of equivalentor similar features.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

It will be appreciated that many of the features described above,particularly of the preferred embodiments, are inventive in their ownright and not just as part of an embodiment of the present invention.Independent protection may be sought for these features in addition toor alternative to any invention presently claimed.

The invention will now be described in more detail by reference to thefollowing examples, which are illustrative only and do not limit thescope of the invention.

Example 1 But-2-ynedioic acid bis-(2-ethyl-hexyl)ester

A mixture of acetylenedicarboxylic acid (25.0 g, 219 mmol), ethylhexanol(103 cm³, 660 mmol), anhydrous toluene (100 cm³) and sulfuric acid (10cm³) is heated at reflux under Dean-Stark conditions for 17 hours. Themixture is allowed to cool, brine (200 cm³) added and the productextracted with ether (2×250 cm³). The combined organic extracts driedover anhydrous magnesium sulfate, filtered and the solvent removed invacuo to give a brown oil. The residue is distilled under vacuum (144°C., 0.07 mBar) to give but-2-ynedioic acid bis-(2-ethyl-hexyl)ester as apale yellow oil (31.9 g, 36%). ¹H NMR (300 MHz, CDCl₃) 0.85-0.95 (12H,m, CH₃), 1.23-1.41 (16H, m, CH₂), 1.57-1.70 (2H, m, CH), 4.11-4.21 (4H,m, OCH₂); ¹³C NMR (300 MHz, CDCl₃) 10.9, 14.0, 22.9, 23.5, 28.8, 30.1,38.6, 69.2, 74.7, 152.1.

4,7-Di-thiophen-2-yl-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acidbis-(2-ethyl-hexyl)ester

A mixture of[4-(thiophene-2-carbonyl)-[2,1,3]thiadiazol-3-yl]-thiophen-2-yl-methanone(1.7 g, 6 mmol), anhydrous toluene (70 cm³) and Lawesson's reagent (3.8g, 9.5 mmol) is stirred at room temperature for 2 hours. But-2-ynedioicacid bis-(2-ethyl-hexyl)ester (3.4 g, 10 mmol) is then added and thereaction mixture heated at reflux for 17 hours. Acetone (50 cm³) isadded, the mixture pre-absorbed onto silica and purified by columnchromatography (40-60 petrol:ethyl acetate; 1:0 to 3:1) to give4,7-di-thiophen-2-yl-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acidbis-(2-ethyl-hexyl)ester as a yellow/green oil (380 mg, 11%). ¹H NMR(300 MHz, CDCl₃) 0.71-0.99 (12H, m, CH₃), 1.03-1.47 (16H, m, CH₂),1.50-1.75 (2H, m, CH), 3.94-4.15 (4H, m, OCH₂), 7.18 (2H, dd, ArH, J3.6, 5.0), 7.41 (2H, dd, ArH, J 1.2, 3.6), 7.58 (2H, dd, ArH, J 1.2,5.0); ¹³C NMR (300 MHz, CDCl₃) 10.9, 14.1, 23.0, 23.3, 28.9, 30.0, 38.4,68.9, 126.0, 127.3, 128.7, 129.6, 132.8, 135.3, 153.7, 167.9.

4,7-Bis-(5-bromo-thiophen-2-yl)-benzo[2,1,3]thiadiazole-5,6-dicarboxylicacid bis-(2-ethyl-hexyl)ester

To a solution of4,7-di-thiophen-2-yl-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acidbis-(2-ethyl-hexyl) ester (360 mg, 0.59 mmol) in dichloromethane (50cm³) and glacial acetic acid (50 cm³) in the dark is addedN-bromosuccinimide (210 mg, 1.18 mmol) and the mixture is stirred atroom temperature for 17 hours. Further N-bromosuccinimide (160 mg, 0.90mmol) is added and the mixture stirred at room temperature for 4 hours.Water (250 cm³) added to the mixture and the product extracted withdichloromethane (2×200 cm³). The combined organic extracts are driedover anhydrous magnesium sulfate, filtered, and the solvent removed invacuo to give a yellow oil. The crude material columned (40-60petrol:ethyl acetate; 1:0 to 3:1) to give4,7-bis-(5-bromo-thiophen-2-yl)-benzo[2,1,3]thiadiazole-5,6-dicarboxylicacid bis-(2-ethyl-hexyl) ester as an orange/yellow oil (140 mg, 31%). ¹HNMR (300 MHz, CDCl₃) 0.78-0.92 (12H, m, CH₃), 1.13-1.33 (16H, m, CH₂),1.39-1.50 (2H, m, CH), 4.01-4.13 (4H, m, OCH₂), 7.12 (2H, d, ArH, J3.9), 7.15 (2H, d, ArH, J 3.9); ¹³C NMR (300 MHz, CDCl₃) 10.9, 14.1,23.0, 23.4, 28.9, 30.1, 38.5, 69.1, 116.4, 125.2, 129.9, 130.1, 132.7,136.8, 153.2, 167.6.

Poly{4,7-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acidbis-(2-ethyl-hexyl)ester}-alt-{5,5(2,6-bis[2-thienyl]-1′-4,8-dioctylbenzo[1,2-b:4,5-b′]dithiophene)}

A mixture of4,8-dioctyl-2,6-bis-trimethylstannanyl-benzo[1,2-b;4,5-b′]dithiophene(133.2 mg, 0.18 mmol),4,7-bis-(5-bromo-thiophen-2-yl)-benzo[2,1,3]thiadiazole-5,6-dicarboxylicacid bis-(2-ethyl-hexyl)ester (138.7 mg, 0.18 mmol),tris(dibenzyl-ideneacetone)dipalladium(0) (1.6 mg, 0.002 mmol),tri(o-tolyl)phosphine (2.2 mg, 0.007 mmol) is subjected to threesuccessive cycles of vacuum followed by refilling with nitrogen. To thisis added degassed anhydrous toluene (5 cm³) and degassed anhydrousN,N-dimethylformamide (1 cm³). The mixture is then heated at 110° C. for17 hours. The mixture is allowed to cool and poured into stirringacidified methanol (10% hydrochloric acid, 50 cm³) and the precipitatestirred for 30 minutes. The solid is then collected by filtration,washed with methanol (100 cm³) to give a black solid. The crude polymeris washed via Soxhlet extraction with acetone, 40-60 petrol andchloroform. The chloroform extract is concentrated in vacuo andprecipitated into stirred methanol (50 cm³). The polymer collected byfiltration and dried under vacuum to givepoly{4,7-benzo[2,1,3]thiadiazole-5,6-dicarboxylic acidbis-(2-ethyl-hexyl)ester}-alt-{5,5(2,6-bis[2-thienyl]-4,8-dioctylbenzo[1,2-b:4,5-b′]dithiophene)}as a black solid (100 mg, 54%). GPC (chlorobenzene) M_(n): 16,600,M_(w): 28,700, pd: 1.73.

Photovoltaic Cell Fabrication and Measurement

Organic photovoltaic (OPV) devices were fabricated on ITO-glasssubstrates (13 Ω/sq.) purchased from LUMTEC Corporation. Substrates werecleaned using common solvents (acetone, iso-propanol, deionized-water)in an ultrasonic bath prior to a conventional photolithography processthat was carried out to define the bottom electrodes (anodes). Aconducting polymer poly(ethylene dioxythiophene) doped with poly(styrenesulfonic acid) [Clevios VPAI 4083 (H. C. Starck)] was mixed in a 1:1ratio with deionized-water. This solution was sonicated for 20 minutesto ensure proper mixing and filtered using a 0.2 μm filter beforespin-coating to achieve a thickness of 20 nm. Substrates were exposed toozone prior to the spin-coating process to ensure good wettingproperties. Films were then annealed at 130° C. for 30 minutes in anitrogen atmosphere where they were kept for the remainder of theprocess. Active materials solutions were prepared at the concentrationand components ratio stated in the examples and stirred overnight. Thinfilms were either spin-coated or blade-coated in a nitrogen atmosphereto achieve active layer thicknesses between 100 and 250 nm as measuredusing a profilometer. A short drying period followed to ensure removalof any residual solvent. Typically, spin-coated films were dried at 23°C. for 10 minutes and blade-coated films were dried at 70° C. for 2minutes on a hotplate. For the last step of the device fabrication, Ca(30 nm)/Al (200 nm) cathodes were thermally evaporated through a shadowmask to define the cells. Samples were measured at 23° C. under theirradiation of 1 Sun using a Solar Simulator (Newport Ltd, Model 91160)as the light source and using a calibrated Si-cell as the reference.

OPV device characteristics for blends of polymer examples (1)-(5) withPC₆₁BM under irradiation of 1 Sun are shown in table 1.

Example 1: 20 mg/ml concentration, 1:2 ratio OPV:PCBM[60]

Example 2: 30 mg/ml concentration, 1:2 ratio OPV:PCBM[60]

Example 3: 40 mg/ml concentration, 1:2 ratio OPV:PCBM[60]

Example 4: 30 mg/ml concentration, 1:1 ratio OPV:PCBM[60]

Example 5: 30 mg/ml concentration, 1:3 ratio OPV:PCBM[60]

TABLE 1 Photovoltaic cell characteristics Example η (%) FF V_(oc) (mV)J_(sc) (mA/cm²) (1) 0.33 29 627 −1.77 (2) 0.33 34 774 −1.25 (3) 0.39 33769 −1.54 (4) 0.33 29 863 −1.35 (5) 0.26 32 750 −1.06

The invention claimed is:
 1. A polymer selected from the followingformulae:

wherein R^(x) and R^(y) are each H or straight-chain, branched or cyclicalkyl with 1 to 30 C atoms, in which one or more non-adjacent C atomsare each optionally replaced by —O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—,O—C(O)—O—, —CH═CH— or —C≡C— and in which one or more H atoms are eachoptionally replaced by F, Cl, Br, I or CN; R¹ and R² are each selectedfrom straight-chain, branched or cyclic alkyl with 1 to 35 C atoms, inwhich one or more non-adjacent C atoms are each optionally replaced by—O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—, —O—C(O)—O—, —CR⁰═CR⁰⁰— or —C≡C—and in which one or more H atoms are each optionally replaced by F, Cl,Br, I or CN, or denote aryl, heteroaryl, aryloxy, heteroaryloxy,arylcarbonyl, heteroarylcarbonyl, arylcarbonyloxy,heteroarylcarbonyloxy, aryloxycarbonyl or heteroaryloxycarbonyl having 4to 30 ring atoms which in each case is unsubstituted or substituted byone or more non-aromatic groups R³; R³ is on each occurrence,identically or differently, F, Br, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN,—C(O)NR⁰R⁰⁰, —C(O)X⁰, —C(O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H, —SO₂R⁰,—OH, —NO₂, —CF₃, —SF₅, optionally substituted silyl, carbyl orhydrocarbyl with 1 to 40 C atoms that is optionally substituted andoptionally comprises one or more hetero atoms, or P-Sp-; R⁰ and R⁰⁰ areindependently of each other H or optionally substituted C₁₋₄₀ carbyl orhydrocarbyl; P is a polymerizable or crosslinkable group; Sp is a spacergroup or a single bond; X⁰ is halogen; and n is an integer >1.
 2. Apolymer according to claim 1, wherein R¹ and/or R² are selected fromprimary alkyl or alkoxy with 1 to 30 C atoms, secondary alkyl or alkoxywith 3 to 30 C atoms, and tertiary alkyl or alkoxy with 4 to 30 C atoms,wherein in all these groups one or more H atoms are each optionallyreplaced by F, or R¹ and/or R² are selected from aryl, aryloxy,heteroaryl and heteroaryloxy that is optionally alkylated or alkoxylatedand has 4 to 30 ring atoms.
 3. A mixture or blend comprising one or morepolymers according to claim 1 and one or more compounds or polymershaving semiconducting, charge transport, hole/electron transport,hole/electron blocking, electrically conducting, photoconducting orlight emitting properties.
 4. A formulation comprising one or morepolymers according to claim 1, and one or more solvents.
 5. A method ofoperating an optical, electrooptical, electronic, electroluminescent orphotoluminescent component or device comprising using a chargetransport, semiconducting, electrically conducting, photoconducting orlight emitting material to emit light, wherein said material comprises apolymer according to claim
 1. 6. An optical, electrooptical orelectronic component or device comprising one or more polymers accordingto claim
 1. 7. A component or device according to claim 6, which isselected from organic field effect transistors (OFET), thin filmtransistors (TFT), integrated circuits (IC), logic circuits, capacitors,radio frequency identification (RFID) tags, devices or components,organic light emitting diodes (OLED), organic light emitting transistors(OLET), flat panel displays, backlights of displays, organicphotovoltaic devices (OPV), solar cells, laser diodes, photoconductors,photodetectors, electrophotographic devices, electrophotographicrecording devices, organic memory devices, sensor devices, chargeinjection layers, charge transport layers or interlayers in polymerlight emitting diodes (PLEDs), Schottky diodes, planarizing layers,antistatic films, polymer electrolyte membranes (PEM), conductingsubstrates, conducting patterns, electrode materials in batteries,alignment layers, biosensors, biochips, security markings, securitydevices, and components or devices for detecting and discriminating DNAsequences.
 8. A component or device according to claim 6, which is anOFET or a bulk heterojunction OPV device.